forensics

Post-mortem a failed GSD auto-mode run. Traces symptom to root cause via `.gsd/` activity, journal, metrics, and lock artifacts, producing a filing-ready bug report with file:line refs and a fix suggestion. Use when asked to "forensics", "post-mortem", "why did auto-mode fail", "trace the stuck loop", "debug the crash", after `/gsd forensics`, or when a session ended in an unexpected terminal state. Reads artifacts only — re-runs nothing.